1. Field of the Invention
The present invention generally relates to a method and apparatus for short-range mobile communications. More particularly, the present invention relates to a method and apparatus for a short-range mobile communication terminal to connect to a short-range network.
2. Description of the Related Art
A Wireless Personal Area Network (WPAN) is a wireless implementation of an existing Personal Area Network (PAN). Compared to a Local Area network (LAN) and a Wide Area Network (WAN), the PAN is a network unique to an individual person, that is, a network that interconnects devices owned by the individual person to enhance his convenience.
As an effort to wirelessly realize the PAN, the Institute of Electrical and Electronics Engineers (IEEE) 802.15 working group set forth the WPAN as a standard for a short-range wireless network and organized four Task Groups (TGs) under it. IEEE 802.15.1, IEEE 802.15.3 & 802.15.3a, and IEEE 802.15.4 are standards for Bluetooth™ (hereinafter “Bluetooth”), high-rate WPAN, and low-rate WPAN (ZigBee™ (hereinafter “ZigBee”), respectively.
A WPAN formed by a short-range mobile communication system such as ZigBee is composed of a plurality of short-range mobile communication terminals. One of the short-range terminals is designated as a coordinator and the other short-range terminals act as routers or end devices. The coordinator broadcasts a synchronization signal, i.e. a beacon to the other short-range terminals to thereby synchronize the routers or end devices, for mutual communications.
A plurality of such WPANs are formed apart from each other by some distance or overlapping with each other over a predetermined area. As a short-range terminal is mobile, it can move from one WPAN to another WPAN. To this end, the short-range terminal should transmit a leave message to a coordinator of an old WPAN that it is currently in connection with, scan neighbor WPANs to detect and access a new WPAN, and get its user to select one of the detected WPANs. Also, the short-range terminal sends request to join to a coordinator of the selected new WPAN. When the coordinator acknowledges the joining request, the short-range terminal completes the joining procedure to the new WPAN.
As described above, scanning of neighbor WPANs and user selection of a WPAN are required for a short-range terminal to connect to a new WPAN. Therefore, the time required to connect to the new WPAN is long, causing inconvenience to a user.